Power Factor Check
Your power factor from the numbers on your bill or your meter.
Enter what you have. The bill’s kWh and kVARh lines give an average for the period; kW and kVA give the peak; volts, amps and kW give one moment at one panel. Any of them tells you how much of your current is doing no work.
Your numbers
Example values. Replace them with yours.
kW and kVA from the bill’s demand lines or a meter: power factor at the moment of the readings, usually the peak.
Peak demand from the bill (“kW”, “Demand”, “Max demand”), or a meter’s kW reading taken at the same moment as the other value.
“kVA”, “kVA demand” or “Apparent demand” on the bill, for the same period as the kW.
Results
0.82
Below the 0.90 threshold common in power-factor clauses. If your rate schedule has one, this shows on the bill; either way the reactive current is filling capacity.
- Apparent power
- 585 kVA
- Reactive power
- 334 kVAR
- Above the real load
- 22%more kVA and current than the same kW at 1.00
- At 0.98
- about 490 kVAwith 97 kVAR, for the same kW
At 0.82, your 480 kW needs 585 kVA, 22% more than the real load, because 334 kVAR of reactive power rides along. The same 480 kW at 0.98 would need about 490 kVA.
- P, real power
- 480 kW
- Q, reactive power
- 334 kVAR
- S, apparent power
- 585 kVA
- S at 0.98
- about 490 kVA
How this is calculated
Power factor is real power divided by apparent power: PF = kW ÷ kVA. From a bill: PF = kWh ÷ √(kWh² + kVARh²). At a panel: kVA = √3 × volts × amps ÷ 1,000, with volts measured between phases. Reactive power: kVAR = √(kVA² − kW²). The same real load at 1.00 needs kVA equal to kW, so the extra apparent power and current now is 1 ÷ PF − 1.
Assumptions
- The bill’s kVARh gives an average; the peak power factor is usually lower.
- Three phases are taken as balanced.
- Harmonic current lowers true power factor further and is not counted here; the survey measures it.
Estimates from your inputs and the formulas shown. They are not a ruling from your utility, a design or a guarantee. A survey and the six-month rental measure the real thing on your own meter.
Your numbers go with your request; nothing is sent until you submit the form.